Re: inhibit the sincos optimization when the target has sin and cos instructions

[Andrew Pinski <pinskia@gmail.com>]

On Fri, May 13, 2016 at 12:58 PM, Richard Biener
<richard.guenther@gmail.com> wrote:
> On May 13, 2016 9:18:57 PM GMT+02:00, Cesar Philippidis <cesar@codesourcery.com> wrote:
>>The cse_sincos pass tries to optimize sequences such as
>>
>>  sin (x);
>>  cos (x);
>>
>>into a single call to sincos, or cexpi, when available. However, the
>>nvptx target has sin and cos instructions, albeit with some loss of
>>precision (so it's only enabled with -ffast-math). This patch teaches
>>cse_sincos pass to ignore sin, cos and cexpi instructions when the
>>target can expand those calls. This yields a 6x speedup in 314.omriq
>>from spec accel when running on Nvidia accelerators.
>>
>>Is this OK for trunk?
>
> Isn't there an optab for sincos?

This is exactly what I was going to suggest.  This transformation
should be done in the back-end back to sin/cos instructions.

Thanks,
Andrew

> ISTR x87 handles this pass just fine and also can do sin and cos.
>
> Richard.
>
>>Cesar
>
>